Decomposition

Decomposition

	Decomposition Decomposition and photosyntesis are the two important processes of an ecosystem. Litter (the organic remains of biological origin) is an organic chemical carrier of nutrients present in different ecosystems. The structural components of litter govern the rate of decomposition. However, the plant or animal materials present a variety of substances in soil which are heterogeneous both physically and chemically.
Even though agriculture started almost 10,000 years ago, the importance of mineral nutrition for plants came to be recognised only in the nineteenth century. In 1840, a French scientist Jean-Baptiste Boussingault showed that plants obtain nitrogen from nitrates in the soil. John Bennet Lawes and J. H. Gilbert in England discovered the fertiliser, superphosphate. In 1852, the first inorganic fertiliser, potassium sulphate was produced in Germany. Several biofertilisers have been commercialised for increasing soil fertility and they form interesting examples of microbial interactions which pave the way for increasing the soil fertility.
Significant gaseous components occur in the carbon and nitrogen cycles and to a lesser extent, in the sulphur cycle. Thus a soil, aquatic or marine microorganism often can fix gaseous forms of carbon and nitrogen compounds. In the sedimentary cycles such as that for iron, there is no gaseous component. Nitrogen, which has stable valence states ranging from -3 as in ammonia to +5 as in nitrate occurs in numerous oxidation states.
Nitrogen is a constituent of amino acids, nucleic acids, amino sugars and their polymers. A large, slowly cycled reservoir for nitrogen is nitrogen gas of the atmosphere. Large but essentially unavailable reservoirs of nitrogen are present in igneous and sedimentary rock as bound, non-exchangeable ammonia.
	Availability of combined nitrogen is an important limiting factor for primary production in many ecosystems. The inorganic nitrogen ions-ammonium, nitrite, and nitrate-occur as salts that are highly water soluble and consequently are distributed in dilute aqueous solution throughout the ecosphere, forming small actively cycled reservoirs.

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